Method and Apparatus for Monitoring Weld Cell

ABSTRACT

A method and apparatus for monitoring weld cell and related activity is disclosed. The activity is sensed using a variety of sensors, and reported to the controller, or to a remote location.

FIELD OF THE INVENTION

The present invention relates generally to the art of weld cells. Morespecifically, it relates to monitoring the activity that occurs in aweld cell.

BACKGROUND OF THE INVENTION

A weld cell is an area or room in which welding and related tasks areperformed. Tracking activity in the weld cell can be used for a varietyof purposes, including helping efficiency, quality, reliability, testingand notifications. This invention relates to tracking welding and/orrelated tasks and/or welding or related information.

Welding can include a tack weld and a final weld. The performance of aweld can includes time during which the arc is on (arc-on time) and timeduring which the gun is in hand. In addition to the time-basedinformation of a weld, related weld information includes the weldparameters (current, voltage, process cycle time, ramp rates, etc).

Related tasks can be varied, and include tasks such as grinding and/orscraping for cosmetics fit up and/or spatter removal, loading parts,unloading parts, looking for parts, moving parts, waiting for parts(from another weld or for delivery), and ordering parts. Many of theserelated tasks are done in an inefficient manner, and many are done by amore highly skilled worker than necessary. For example, welding oftenrequires a high level of skill, but moving parts does not. Otherinformation that can be desirable relates to the operator, such ashealth and safety information (heart rate, heat stress or core or headbody temperature, movement, pinch points (i.e., hands, fingers, toes,feet, etc. . . . ), fume exposure, repetitive motion. It is alsodesirable to know quality metrics such as Overall EquipmentEffectiveness (OEE), Overall Process Effectiveness (OPE), weld sequence,time spent waiting, and pre-heat, inter-pass and post temperature.

Many companies are pursuing lean manufacturing, six sigma principles,single piece flow, etc., in an effort to improve efficiency. Thebreakdown of activities of the employee(s) and an understanding of wasteand through-put constraints in manufacturing is useful information,particularly for continuous improvement. Reducing or eliminatingreducing non-value added bottle necks and activities can improvethroughput and overall weld time. Operators often spend more timegrinding and fitting parts than welding but data to determine therelative times are not readily available. Given the lack of informationand hard data regarding weld cell activity changing production flow issometimes done as a matter of guesswork, instead of based on hard facts.Data is needed to know when and how to make changes, as wells as toevaluate the result of the change. Such data has been particularlydifficult to obtain in a weld cell.

Accordingly, a method and apparatus for tracking well cell activity isdesired.

SUMMARY OF THE PRESENT INVENTION

According to a first aspect of the invention a welding type systemincludes a power source, a controller and at least one weld cellactivity sensor.

According to a second aspect of the invention a system for tracking weldcell activity includes a first sensor disposed to be responsive to atleast a first weld cell activity. A transmitter that is connected to thefirst sensor transmits information indicative of the at least a firstweld cell activity. A receiver receives the transmitted information.

The sensor includes an RF transmitter disposed to transmit informationindicative of the activity tracked in one embodiment.

The controller includes a network or internet gateway/interface forproviding the transmitted information over the network in anotherembodiment.

The transmitted information provided over the network includestime-related data and/or relates to one or more of the arc being on, thegun being on, time spent grinding, time spent sanding, time spentloading, time spent waiting for a temperature, and time spent fitting upin various embodiments.

Additional sensors are provided in various embodiments.

Other principal features and advantages of the invention will becomeapparent to those skilled in the art upon review of the followingdrawings, the detailed description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is block diagram showing one embodiment of the present invention;and

FIG. 2 is block diagram showing one embodiment of the present invention.

Before explaining at least one embodiment of the invention in detail itis to be understood that the invention is not limited in its applicationto the details of construction and the arrangement of the components setforth in the following description or illustrated in the drawings. Theinvention is capable of other embodiments or of being practiced orcarried out in various ways. Also, it is to be understood that thephraseology and terminology employed herein is for the purpose ofdescription and should not be regarded as limiting. Like referencenumerals are used to indicate like components.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

While the present invention will be illustrated with reference toparticular activities and particular ways of tracking and reportingthose activities, it should be understood at the outset that theinvention can also be implemented to track and report other activities,and in other manners. A weld cell typically includes a welding system,including a power source and a controller. The present invention can beintegrated with the controller and sense the output of the power sourceas needed, or it can be stand alone system used with or without a powersource.

Some weld cell activities/values tracked in accordance with the presentinvention include final weld, tack weld (time spent in either weldingoperations can be determined using arc-on time, weld parameters, gun inhand time), scraping, grinding, waiting, loading and unloading. Variousmethods and sensors for tracking will be described with respect to oneor more particular weld cell activities, but it is intended they couldbe used with other weld cell activities, and/or they could be combinedas desired to make a more useful, robust or economical sensing method.Weld cell activity, as used herein, includes one or more of the taskscommonly performed in a weld cell. Weld cell activity tracking sensor isa sensor that detects when a weld cell activity starts, ends, or isbeing performed.

After the information is sensed it can be provided to the welding systemcontroller, or it can be transmitted outside the weld cell, such as tothe plant operator, manager, etc. The transmission can be wired orwireless. In the preferred embodiment a Monnit® RF sensor system isused. The information is sensed, transmitted by RF to a network orinternet gateway, and then provided over the internet to a monitoringserver, and then provided on a graph, chart, to a pc, on a dashboard, byemail, etc., if desired, to the plant operator, supervisor or others.The data provided is preferably time related data for the activity. Timerelated data for an activity, as used herein, is data responsive to thebeginning, end or duration of a weld cell activity. A network interfaceis an interface that allows information to be sent or received over anetwork. An internet gateway is a gateway that allows information to besent or received over the internet,

For example, a reed switch can be placed around a weld cable, and theoutput of the reed switch provided to the RF sensor system. When the arcis on, the magnetic field from the current in the weld cable is sensedby the reed switch, and the RF transmitter sends a signal. That signalis responsive to the arc being on. When the arc is off, the reed switchchanges state, and another RF signal can be sent, indicating the arc isoff. An alternative embodiment provides that RF signals are repeatedlysent so long as the arc is on. Thus the absence of the RF signalindicates the arc is off. The gateway receives the RF signals andprovides the information over the internet. The on/off times are used todetermine the arc on time (the difference between RF signals or theduration of repeated RF signals.

Grinding/sanding can be done for parts fit up and for spatter removal.The invention can be used to detect time needed for grinding/sanding foreither reason. amount of time an operator is grinding or sanding. Oneembodiment provides that time spent operating the grinder/sander andtime spent on “air moves” with grinder in hand (such as getting thegrinder from its resting place, moving to the part, moving around thepart, positioning the part, positioning your body, putting grinder back,etc) are tracked. The manner in which the time operating the grindingand time on air moves are tracked can be any of the methods discussedherein.

Multiple methods are possible to attempt to record the operator's timeallocation. Many of these techniques will be useful for sensing otheractivity in the weld cell. These include those described below withrespect to other activities and current sense, air flow sense,triangulation of position, hose retract sensor, visual-spark detection,count of discs consumed per day (combined with manual recording),grinding face shield usage/consumption, vibration on grinding shield,vibration on fixture, kineseology motion monitoring, acousticmonitoring, deriving data from a robot (for air moves, e.g.).

One embodiment provides for sensing the source of power for the device(current, air, hydraulics . . . ) and can be used for a number ofactivities, including grinding and sanding. Also, a reed switch, halleffect, or other current sensor on the grinder power cord could be usedto detect operation of the grinder. GPS location of the tool and/oroperator via some form of triangulation, pressure sensors in floor mats,and/or light can be used to locate the operator, and/or tool and used toidentify many activities in the weld cell. Sensing when the hose, cord,etc. is pulled from the retract spool is another method able to detectmany activities. Sensing when sparks are being made (light) can be usedto detect grinding or sanding (time when it is actually occurring).Recording the in use time (from sparks, e.g.) and the total time a toolis off a shadow board allows inference of the time spent on air moves.Recording the number of consumables (sanding/grinding discs) allowsinferring the time spent actually grinding or sanding. Sensing adistinct vibration of a fixture from using of a particular tool, and/orsensing actual motion and/or position of an operator to identifylocation and action (certain locations/actions would be tied toparticular activities) can be used with many activities. Usingparticular protective equipment tied to particular activities (faceshield for grinding) can also be a way to track time spent on anactivity. Certain tools have certain sound characteristics which can beused to identify an activity (with or without directional microphones).Sensors can be combined (floormat#1+hammer sound=hammering at stationone, floor mat #2+hammer sound=hammering at station 2), or using soundand a shadow board, sound and sparks, etc. Sensing air or shielding gasflow could be used to detect when a tool or welding power supply is inuse. For example, sensing flow of air for an air power grinder or otherair powered tools, or shielding gas for a welding power supply, could beused to determine when the grinder, tool or power supply is being used.

One embodiment provides for choosing the method/sensors that provide themost useful data relative to least amount of cost for the sensors.Another embodiment uses an unobtrusive sensor to reduce the likelihoodthat the operator's actions are affected by the monitoring.

The sensor(s) are preferably tied to a data collection method that willconvert the data to information in a clear and intuitive format.Initially, it may dump the data to common data format like Excel®spreadsheet, or a database, which then can be manipulated. The endresults are pie charts of time spent, particular activities can beflagged and tallied separately, time of day breakdowns of activity,flagged activities (say non value added), health and safety concerns,quality and/or process and production metrics can be highlighted in redand displayed in a visual format by operator, work station, time of day,shift, day and/or automatic pareto reporting.

With respect to scraping, various sensors and methods to sense whenscraping is being performed is to monitor the resting place for scraper,use an RF tag on scraper and/or operator, have a sensor on the scraperthat sense a parameter such as force, etc., use an electrical signal onscraper/part, use a localized GPS device on scraper, scan a bar code onthe scraper and/or glove, motion sensor such as a simple accelerometeron scraper, a USB/data port (including wireless) on scraper, a sensorthat detects wearing of the scraper, a permanent magnet on scraper tocollect spatter (which correlates to the amount of spatter), manualrecording of scraper use, a scanner to check-in and check-out tools(inhibit until check-in or don't use check-in) such as a bar codescanner, image recognition scanner, weight sensor, RF scanner, videorecognition (one robust technique is to use a white board with darktools or parts thereon) or audio signature—in helmet, safety glasses,grinding shield, temperature sensing (the scraper get hot when used, orsense the heat of the hand holding it), vibration sensing—in part,glove, fixture, tool, helmet on/off sensor, operator motion/physicalexertion, voice recognition in helmet—“Grinding” . . . “Welding” . . . ,warming from hand, pressure sensor on handle, pressure sensor on toolboard. Each of these sensors/methods may be used to identify the timespent scraping. They may also be used with other weld cell activities,such as that described above or below, to determine the time spent doingsuch activity. The system can include a learning mode where the userteaches the system. For example, in the learning mode the user cangrind, and the system creates an audio signature in response to thetaught sound. Teaching could also be used with video recognition or theother types of sensing.

Other weld cell activities that can be monitored using the sensors andmethods described above and below include inspection of parts, reading aprint, compensating (hammering, bending, prying), pre-heating,cambering, looking for parts, using a chipping hammer, wire brushing,using tempil sticks (or measuring temperature in other manners), using aneedle gun and waiting. With respect to some activities it is useful toknow why it is occurring. For example, waiting can occur when the welderis waiting for supervisor, for help, for a crane, for pre-heat temp, forparts, for inter-pass temperature to be reached, resting, for cool-down,for maintenance issues, etc. Determine why the welder is waiting can bethe first step in making the process lean, Waiting can be avoided byimproving communication systems, anticipating events that cause waiting,and automating the communication/reporting of the cause that someone iswaiting. Monnit® sensors are available that sense temperature, infraredmotion, an ID, light, lux (light intensity) open/closed position,magnetic presence, activity, acceleration, current, voltage, and otherproperties are available. These, or custom sensors, can be used todetect the activity.

Determining the reason for waiting can be done using the sensingdescribed above or below with respect to other activities, or by sensingtype of motion, sensing movement without vibration, etc, gps, audiosensor, voice recognition, absence of other (sensable) activity,pre-coded keys on helmet, helmet “flip-up” time, weight of wire onfeeder, sense empty fixture, and sense time between sequences. Each ofthese sensors and methods can be used to monitor other activities in andrelating to the weld cell.

Time spent loading and unloading can be determined by sensing weight oncrane, weight/pressure sensor on fixture, clamps open/closed, timebetween welding sequences, video—part motion, light/laser sensor onfixture, crane motion, sensing part shadow board/kan ban bin, # ofpeople in cell, hard hat on (temp/pressure sensor), audio sensor, aswell as the sensors described above and below with respect to otheractivities.

The various sensors are, in one embodiment networked, wired or wireless,or CAN/LAN technology, with or without GPS so the operator, manager etccan determine what and how to resolve non-value added activities. USB/SDcards or other removable storage can be used.

A current sensor on the welding machine with a common 115 volt circuiton the machine and some current threshold slightly lower than a grindercurrent draw level or the outlet designated to the plug for the grinderwith some current threshold would be helpful in monitoring non-weldingactivity. The welding machine may store the amount of time grindingoccurred for a given period of time plus build a tracking and history ofthe amount of time grinding occurs for some time that is accessible viainternet, USB/SD, GPS, LAN, Ethernet/CAN and wire/wireless networks. Asimilar device is a device that plugs into 115 or 230 volts in thefactory bus system or welding machine and has a similar currentthreshold that senses time and draw deterministic of grinding. Thedevice plugs into the 115 volts or 230 volts and the grinder or otherdevice plugs into this unit. This device added to the outlet would havea similar capability to use internet, USB/SD, GPS, LAN, Ethernet/CAN andwire/wireless networking to monitor.

Such a current sensor could operate on 115 volts or 230 volts and couldbe used on hoists, hydraulic motors/pumps, robots/automation devices,and other devices used in manufacturing welded products. These devicesfeeding a hub of data determining where the operator spends time arevaluable sources of information to first understand and then determinemethods to reduce these non-value added activities in the way ofcorrective actions and justification for different forming processes,tooling and welding processes that may create the need for grinding andother non-value added activities. The system or hub of data would havethe ability to summarize activity by looking in the time and frequencydomain and reporting graphs, bar charts and other common methods ofstatistical analysis. These systems may be taught the current draw byputting the device into the teach mode and running grinders, hoists etc.to establish a threshold.

Another sensor/method uses a reflective tag or light such as led sourcecould be placed on the operators head or body and the cell would haveone or more cameras to determine location of the operator and where heor she spends time doing grinding versus welding. This could be usedwith other information such as the current draw method stated earlier.The system would take camera information and put it into the frequencydomain and assess location and time domain to determine amount of timein a location. This method would filter non-recurring locations oractivities or activities of insignificant time to reduce computing timeand demands. The camera and associated software should have the abilityto work on network. Another embodiment uses RF receivers with trackingzones of where is the operator activity. The operator may wear thereceiver or the RF emitting device. The various tools may have an RFdevice on them or the receiver may be on the tool versus the operator toestablish how much time per tool for the operators activities includinggrinding, hoists and tooling. Even how much time the operator looks atprints, job packets and waiting for parts may be tracked.

Another embodiment provides for using microphones or a microphone in themanufacturing cell to determine the overall time of a given activity dueto the specific audible frequency of grinding versus welding or using ahoist. These are very specific sounds but not easy to filter out of thebackground noise to determine what activities and how much time is beingspent on a given activity in a manufacturing process. This sound must befiltered and looked at in the frequency domain and compared to typicalnoise footprints such as a typical grinder or hoist or hammer. This,known footprint, however, may be taught by putting the system in atraining mode and running the tool due to the difference in sound of agrinder from one company to another or tool to tool. The sound analysissystem may be connected to a network for analysis by the manufacturingengineer or welding engineer or operator for continuous improvement andthe reduction of non-value added time.

The system may also communicate to the MRP or ERP system so the partwelded is known as well as logging the operator identification or otherquality and material tracking information. Therefore, management can seetrends by employee and part being made. Also, trends can be evaluated inwho did the cutting and machining of parts to look for time relateddelays.

Other weld cell activities that can be tracked using the sensors/methodsdescribed herein include adjusting/changing ppe (personal protectionequipment), entering/leaving cell, training, maintenance, fixturing,adjusting welder/machine, rework-correcting mistakenparts—gouging/re-welding, etc., helping another cell, positioning,walking, reporting, talking—communicating with supervisors, etc, breaks,meetings, cleaning (sweeping, organizing, etc), exchanging/switchingtools, changing cell layout, changing tool locations,exercising/stretching, operator safety—heat, motion, etc., laying outparts, moving parts, and install/remove spreader bars,

Other activities that relate to welding, that may be with or outside ofthe weld cell, could also be tracked, such as procurement—partsordering, part fabrication area (cutting/forming/stamping), paint line,final assembly, testing, logistics—movement between the above cells,integration of all of the above into weld cell, service tech monitoring,and who is the operator. These may be tracked using many of themethods/sensors described herein.

Tracking some or many of the activities described herein will allowmanufactures to implement continuous improvement, six sigma and leanprinciples in the weld cell, by providing the data used to makedecisions on how to improve.

Other tasks/tools/items that can be monitored include operator, healthand safety such as heart rate, heat stress or body temperature (core,head, etc. . . . ), movement, pinch points (i.e., hands, fingers, toes,feet, etc. . . . ), fume exposure, repetitive motion, and qualitymetrics such as Overall Equipment Effectiveness (OEE), Overall ProcessEffectiveness (OPE), weld sequence, waiting for x, time spent waiting,pre-heat temperature, inter-pass temperature, post temperature, andthese can be automatically reported (with other issues) to management.Such automatic reporting, as well as other reporting is preferably doneusing software modules. The location of other “moveable” tools,fixtures, parts racks, shadow boards, welding consumables, parts,sub-assemblies, ventilation hoods/equipment (especially relative to thewelding gun), overhead cranes, cherry-pickers, positioners, hoists,booms, etc can be tracked, as can the operator location relative to theweldments, as can other tools such as pneumatic or electric hand tools(torque guns, drivers, air-hammers, air-chisels, etc. . . . ), paint orother fluid spray equipment, cutting equipment, etc.

Additional sensors that could be used include sensors such as thoseabove or others that are incorporated into the tools and equipment, andthis can reduce the obtrusiveness to an operator. Many of the sensorsdiscussed herein could be wireless. Microelectromechanical systems(MEMS) based sensors for accelerometers, activity, etc. could also beused. The sensors above are sometimes described with respect to one ormore particular tasks, tools etc., but can be used for any task, tool,etc.

The invention can be used to implement lean manufacturing, six sigmaprinciples, single piece flow, continuous improvement, etc., in aneffort to improve efficiency. The breakdown of activities of theemployee(s) and an understanding of waste and through-put constraints inmanufacturing obtained as described herein is useful information forsuch efficiency improvements. Date to determine where activity occurs,when it occurs, and for how long it occurs, can be used to prioritizeand assess how to reduce these activities. The data obtained asdescribed herein can also be used to monitor the effect of changes—todetermine whether a change that has been implemented results in theefficiency gains expected.

The invention could also be used with other manufacturing/fabricationenvironments that require skill and manual interaction.

FIG. 1 is a schematic showing a system 100 that controls and receivesdata from various sensors and the welding power supply. A networkconnection is also shown. A welding power source 104 has two-waycommunication with a controller 102. The communication can includetypical control and feedback signals.

A loading sensor 116 senses when the part to be welded is being loadedinto the fixture. The sensor is preferably a motion based sensor, andincludes a time stamp when the loading begins. The begin loading timestamp is provided to controller 102. A tack weld sensor 108 detectswelding current used for tack welding, and provides a signal with a timestamp to controller 102, indicating tack welding has started. The tackweld sensor can be a reed switch, combined with the welding output beingappropriate for tack welding (as determined by controller 102).Controller 102 then determines the elapsed time between the beginning ofthe loading and the beginning of the next activity (a tack weld in thisexample). That difference between the time stamps (or a measured elapsedtime) is the time spend fitting up or loading.

After a tack weld the operator begins a final weld, The final weld isdetected using sensor 110, which senses current in the weld cable, withthe welding output having a setting appropriate for final weld.Alternatively, current feedback from the welding power source indicatesthe tack or final weld is being performed. A single sensor can be usedfor both tack and final weld, when combined with information indicativeof whether the output is a final or tack output. The time for the tackweld is determined by the controller based on the start of the tackweld, and the start of the next activity (in this example final weld).

The operator begins grinding next, in this example. To retrieve thegrinder the operator walks across the weld cell. A plurality of sensor114 in the floor mats detect the movement of the operator. Sensors 114are preferably pressure sensitive sensors. The output of sensors 114 isprovided to controller 102, which determines the location to which theoperator walked is the location of the grinder. The operator walks backto the weldment, and begins grinding. A sensor 106, such as a currentsensor on the aux power line detects that the aux power is being used.Sensor 106 could also be an air flow switch on the air supply for thegrinder. That information, and the information from sensors 114, allowthe controller to determine that grinding is taking place. Controller102 could similarly detect sanding, either using the same aux powersensor and floor mat sensors, or using a separate sensor on the sanderpower cord.

Having obtained the time spent fitting up, tack welding, final welding,and grinding, controller 102 summarizes that information in a easilyread table, chart or spread sheet. That information is provided via anetwork connection and over a network or internet 118 to the manager.Alternatives provide for looking at time spent walking (sensed via floormats) as a separate activity. Other alternatives provide that othersensors, for example those described herein, are used. Anotheralternative provides using RF transmitters to send the information to agateway, and then to the internet. Another alternative provides that thesignals provided to controller 102 do not include a time stamp, butmerely indicate the beginning or end of the activity, and controller102, or other downstream device, or an intelligent sensor, adds the timestamp (or merely measures an elapsed time).

FIG. 2 is a schematic showing another embodiment of the invention. Thisembodiment is similar to that of FIG. 1, but activity tracking system200 includes a gateway 203, which receives the signals form each of thesensors. Gateway 203 then provides the information to internet ornetwork 118. Welding system 202 includes controller and power source.The sensors may be those described above. Alternatively, each sensor isa Monnit® RF sensor that transmits to gateway 203 wirelessly. A weldsensor 211 is an RF magnetic field sensor, or a light sensor (to detectthe arc). A grinding sensor 206 and a sanding sensor 212 include a reedswitch and RF sensor on the power cords for the grinder and sander.Walking sensor 214 includes either pressure sensors in the floor mats ormotion sensors. Loading sensor 216 includes a motion sensor. The timespent determination is performed remotely after the data is transmittedto network 118, by comparing start and stop times, or start and nextactivity start times. The information provided on internet 118 is anemail, in one embodiment.

After data is sent to the internet, the data may be stored in a databaseand then analyzed to create graphs, pie charts, or dashboard, and thenprovided to the plant manager or others, such as via the internet to aserver or to a personal computer.

Another alternative applies the above invention to areas outside theweld cell such as metal cutting, metal bending, painting, materialmanagement, finished assembly and so forth. Sensing can be done in themanner described above, and information reported via a gateway orcontroller to the managers, supervisors, or others. Both low volume/highmix or high volume/low mix production tracking is conceived. Theactivities sensed and/or tracked, and information provided, includerates of production, material flow, part tracking, assembly rates,events, quality measurements, and other shop floor activity/associatedinformation that can be combined, analyzed, processed and then displayedon dashboards, graphs on PCs or shop floor displays, or within keyperformance metrics of a production facility. The increasedunderstanding of the factory floor facilitates informed decision makingand continuous improvement.

Numerous modifications may be made to the present invention which stillfall within the intended scope hereof. Thus, it should be apparent thatthere has been provided in accordance with the present invention amethod and apparatus for tracking weld cell activity that fullysatisfies the objectives and advantages set forth above. Although theinvention has been described in conjunction with specific embodimentsthereof, it is evident that many alternatives, modifications andvariations will be apparent to those skilled in the art. Accordingly, itis intended to embrace all such alternatives, modifications andvariations that fall within the spirit and broad scope of the appendedclaims.

1. A welding system that includes a weld cell activity tracking sensoroperatively connected to a welding system controller.
 2. The system ofclaim 1, wherein the sensor includes an RF transmitter disposed totransmit information indicative of the activity tracked.
 3. The systemof claim 2, further comprising a network connection connected to thecontroller, wherein the controller includes a network interface disposedto provide the transmitted information over the network.
 4. The systemof claim 3, wherein the transmitted information provided over thenetwork includes time-related data.
 5. The system of claim 3, whereinthe transmitted information is indicative of at least one of the arcbeing on, the gun being on, time spent grinding, time spent sanding,time spent loading, time spent waiting for a temperature, and time spentfitting up.
 6. The system of claim 1, further comprising at least asecond weld cell activity tracking sensor operatively connected to thewelding system controller.
 7. A system for tracking weld cell activity,comprising: a first sensor disposed to be responsive to at least a firstweld cell activity; a transmitter, connected to the first sensor, anddisposed to transmit information indicative of the at least a first weldcell activity; and a receiver, disposed to receive the transmittedinformation.
 8. The system of claim 7, wherein the transmitter is an RFtransmitter.
 9. The system of claim 8, further comprising an internetgateway responsive to the RF transmitter, and disposed to provide thetransmitted information over the internet.
 10. The system of claim 9,wherein the transmitted information provided by the gateway includestime-related data.
 11. The system of claim 9, wherein the transmittedinformation is indicative of at least one of the arc being on, the gunbeing on, time spent grinding, time spent sanding, time spent loading,time spent waiting for a temperature, and time spent fitting up.
 12. Thesystem of claim 7, further comprising: a second sensor disposed to beresponsive to at least a second weld cell activity; and a secondtransmitter, connected to the second sensor, and disposed to transmitinformation indicative of the at least a second weld cell activity;wherein the receiver is further disposed to receive the transmittedinformation indicative of the at least a second weld cell activity. 13.The system of claim 12, further comprising: a third sensor disposed tobe responsive to at least a third weld cell activity; and a thirdtransmitter, connected to the third sensor, and disposed to transmitinformation indicative of the at least a third weld cell activity;wherein the receiver is further disposed to receive the transmittedinformation indicative of the at least a third weld cell activity.